Aqua(6,6′-oxydipicolinato-κ2 O,N,N′,O′)copper(II)

In the title complex, [Cu(C12H6N2O5)(H2O)], the CuII ion is in a slightly distorted square-pyramidal coordination environment with two N and two O atoms from a 6,6′-oxydipicolinate ligand occupying the basal plane and a water ligand in the apical site. The dihedral angle between the two pyridine rings is 5.51 (6)°. In the crystal structure, intermolecular O—H⋯O hydrogen bonds link molecules into a two-dimensional network. In addition, weak intermolecular C—H⋯O and C=O(lone pair)⋯π(ring) interactions, with O⋯ring-centroid distances of 3.697 (4) and 3.094 (4) Å, provide additional stabilization.

In the title complex, [Cu(C 12 H 6 N 2 O 5 )(H 2 O)], the Cu II ion is in a slightly distorted square-pyramidal coordination environment with two N and two O atoms from a 6,6 0 -oxydipicolinate ligand occupying the basal plane and a water ligand in the apical site. The dihedral angle between the two pyridine rings is 5.51 (6) . In the crystal structure, intermolecular O-HÁ Á ÁO hydrogen bonds link molecules into a two-dimensional network. In addition, weak intermolecular C-HÁ Á ÁO and C O(lone pair)Á Á Á(ring) interactions, with OÁ Á Áringcentroid distances of 3.697 (4) and 3.094 (4) Å , provide additional stabilization.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: LH2964).
of compounds, we report here the synthesis and crystal structure of the title compound (I).
The molecular structure of the title compound (I) is shown in Fig. 1. The Cu II ion is in a slightly distorted square-pyramidal coordination environment with two N and two O atoms from a 6,6'-oxydipicolinato ligand occupying the basal plane and one water ligand in the apical site. The dihedral angle between the two pyridine rings is 5.51 (6)°. The delocalization of electrons within the carboxylate groups is reflected in the C═O lengths. In the crystal structure, there are intermolecular O-H···O hydrogen bonds involving the carboxyl oxygen atoms and coordinated water molecules (Fig. 2) forming a twodimensional network (see Table 1 for hydrogen bond geometries). In addition to weak intermolecular C-H···O interactions, further stabilization appears to be provided by weak C=O(lone pair)···π(ring) stacking interactions (Choudhury et al., 2008).

Experimental
All reagents were available commercially and were used without further purification. 6,6'-Oxydipicolinic acid (260 mg) was added to 1 mmol (132 mg) of CuCl 2 in 10 ml of water. The suspension was stirred for 4 h and filtered. After leaving the filtrate in air for one week, blue block-shaped crystals of (I) were formed. The crystals were isolated, washed with water three times and dried in a vacuum desicator using silica gel (Yield 75%).  Fig. 1. The molecular structure of (I) showing 50% proability displacement ellipsoids and the atom-numbering scheme.  Crystal data [Cu(C 12

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2sigma(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.